Picasso, Matisse, or a Fake? Automated Analysis of Drawings at the Stroke Level for Attribution and Authentication

This paper proposes a computational approach for analysis of strokes in line drawings by artists. We aim at developing an AI methodology that facilitates attribution of drawings of unknown authors in a way that is not easy to be deceived by forged art. The methodology used is based on quantifying the characteristics of individual strokes in drawings. We propose a novel algorithm for segmenting individual strokes. We designed and compared different hand-crafted and learned features for the task of quantifying stroke characteristics. We also propose and compare different classification methods at the drawing level. We experimented with a dataset of 300 digitized drawings with over 80 thousands strokes. The collection mainly consisted of drawings of Pablo Picasso, Henry Matisse, and Egon Schiele, besides a small number of representative works of other artists. The experiments shows that the proposed methodology can classify individual strokes with accuracy 70%-90%, and aggregate over drawings with accuracy above 80%, while being robust to be deceived by fakes (with accuracy 100% for detecting fakes in most settings)

Pilot investigation of remote sensing for intertidal oyster mapping in coastal South Carolina: a methods comparison

South Carolina’s oyster reefs are a major component of the coastal landscape. Eastern oysters Crassostrea virginica are an important economic resource to the state and serve many essential functions in the environment, including water filtration, creek bank stabilization and habitat for other plants and animals. Effective conservation and management of oyster reefs is dependent on an understanding of their abundance, distribution, condition, and change over time. In South Carolina, over 95% of the state’s oyster habitat is intertidal. The current intertidal oyster reef database for South Carolina was developed by field assessment over several years. This database was completed in the early 1980s and is in need of an update to assess resource/habitat status and trends across the state. Anthropogenic factors such as coastal development and associated waterway usage (e.g., boat wakes) are suspected of significantly altering the extent and health of the state’s oyster resources. In 2002 the NOAA Coastal Services Center’s (Center) Coastal Remote Sensing Program (CRS) worked with the Marine Resources Division of the South Carolina Department of Natural Resources (SCDNR) to develop methods for mapping intertidal oyster reefs along the South Carolina coast using remote sensing technology. The objective of this project was to provide SCDNR with potential methodologies and approaches for assessing oyster resources in a more efficiently than could be accomplished through field digitizing. The project focused on the utility of high-resolution aerial imagery and on documenting the effectiveness of various analysis techniques for accomplishing the update. (PDF contains 32 pages

An examination of automatic video retrieval technology on access to the contents of an historical video archive

Purpose – This paper aims to provide an initial understanding of the constraints that historical video collections pose to video retrieval technology and the potential that online access offers to both archive and users. Design/methodology/approach – A small and unique collection of videos on customs and folklore was used as a case study. Multiple methods were employed to investigate the effectiveness of technology and the modality of user access. Automatic keyframe extraction was tested on the visual content while the audio stream was used for automatic classification of speech and music clips. The user access (search vs browse) was assessed in a controlled user evaluation. A focus group and a survey provided insight on the actual use of the analogue archive. The results of these multiple studies were then compared and integrated (triangulation). Findings – The amateur material challenged automatic techniques for video and audio indexing, thus suggesting that the technology must be tested against the material before deciding on a digitisation strategy. Two user interaction modalities, browsing vs searching, were tested in a user evaluation. Results show users preferred searching, but browsing becomes essential when the search engine fails in matching query and indexed words. Browsing was also valued for serendipitous discovery; however the organisation of the archive was judged cryptic and therefore of limited use. This indicates that the categorisation of an online archive should be thought of in terms of users who might not understand the current classification. The focus group and the survey showed clearly the advantage of online access even when the quality of the video surrogate is poor. The evidence gathered suggests that the creation of a digital version of a video archive requires a rethinking of the collection in terms of the new medium: a new archive should be specially designed to exploit the potential that the digital medium offers. Similarly, users' needs have to be considered before designing the digital library interface, as needs are likely to be different from those imagined. Originality/value – This paper is the first attempt to understand the advantages offered and limitations held by video retrieval technology for small video archives like those often found in special collections

Access to recorded interviews: A research agenda

Recorded interviews form a rich basis for scholarly inquiry. Examples include oral histories, community memory projects, and interviews conducted for broadcast media. Emerging technologies offer the potential to radically transform the way in which recorded interviews are made accessible, but this vision will demand substantial investments from a broad range of research communities. This article reviews the present state of practice for making recorded interviews available and the state-of-the-art for key component technologies. A large number of important research issues are identified, and from that set of issues, a coherent research agenda is proposed

Astrometry with "Carte du Ciel" plates, San Fernando zone. I. Digitization and measurement using a flatbed scanner

We present an original method of digitizing and astrometrically reducing "Carte du Ciel" plate material using an inexpensive flatbed scanner, to demonstrate that for this material there is an alternative to more specialized measuring machines that are very few in number and thus not readily available. The sample of plates chosen to develop this method are original "Carte du Ciel" plates of the San Fernando zone, photographic material with a mean epoch 1903.6, and a limiting photographic magnitude ~14.5, covering the declination range of -10 < dec < -2. Digitization has been made using a commercial flatbed scanner, demonstrating the internal precision that can be attained with such a device. A variety of post-scan corrections are shown to be necessary. In particular, the large distortion introduced by the non-uniform action of the scanner is modelled using multiple scans of each plate. We also tackle the specific problems associated with the triple-exposure images on some plates and the grid lines present on all. The final measures are reduced to celestial coordinates using the Tycho-2 Catalogue. The internal precision obtained over a single plate, 3microns ~ 0.18" in each axis, is comparable to what is realized with similar plate material using slower, less affordable, and less widely available conventional measuring machines, such as a PDS microdensitometer. The accuracy attained over large multi-plate areas, employing an overlapping plate technique, is estimated at 0.2".Comment: 16 pages, 19 figures and 3 tables. Accepted for publication in A&

Comparative analysis of 3d digitization systems in the field of dental prosthetics

Amongst the modern engineering technologies which have found broad application in the field of dentistry, one of the most widely used is the 3D digitization. This paper deals with the application of 3D digitization systems in the field of dental prosthetics, and attempt to contribute in this field through comparative analysis of this kind of systems. Special attention is focused on extra oral 3D digitization systems and among them on non specialized dental 3D digitization systems. Beside the general overview and analysis of nine different systems, this paper presents experimental results of comparative accuracy analysis of two high-end 3D digitization systems - Atos II Triple Scan and Zeiss Metrotom 1500. Investigation was based on CAD inspection technique and included 3D and 2D cross sectional analysis. Results related to 3D analysis show that the majority of deviations are in positive direction, concentrated around 0,025 mm. Results of 2D analysis implicate the conclusion that the accuracy of the analysed systems is dependent on surface shape as well as on the model position during the process of 3D digitization

Analysis of digitization methods for edentulous jaws

This study evaluated the trueness and precision of direct digitization and indirect digitization of an edentulous maxilla. An edentulous jaw model made of PEEK, featuring four hemispherical geometries on the alveolar ridge, served as the testing model. The PEEK model was industrially digitized to obtain a reference dataset (REF). Subsequently, the model was digitized according to the clinical workflow (n=25/group) with the following IOS: Cerec Primescan AC (PRI); Trios 3 Wireless (TRS); True Definition (TRD); iTero Element (ITE); Cerec AC Omnicam (OMN). In addition, conventional impressions were taken with scannable PVS (Flexitime Fast&Scan light flow and Flexitime Monophase Pro Scan) and scanned (n=25/group) with laboratory scanners: D810 (D8I) and In EOS X5 (E5I). The impressions were poured, and the resulting stone casts were scanned (n=25/group) with D810 (D8M) and In EOS X5 (E5M). Linear and angular parameters were measured in the virtual model data and compared to REF. One-way ANOVA detected significant differences for all tested parameters. The highest trueness in the P17-P13 and the P17-P23 distances was revealed by group E5I, and in the P17-P27 distance by group PRI. Regarding angular parameters in the transverse plane group, D8M showed the best trueness with no significant difference to any other group, while in the sagittal plane E5M exhibited the highest trueness. Group D8I was most precise in all linear parameters and angle XZ, while group E5I exhibited the highest precision in angle YZ. Digitization of conventional impressions presented the most accurate results. PRI demonstrated values similar to impression digitization and superior to stone cast digitization, while TRS and OMN performed similarly to stone cast digitization.Diese Studie bewertete die Richtigkeit und Präzision direkter und indirekter Digitalisierung eines zahnlosen Oberkiefers. Als Testmodell diente ein zahnloses Oberkiefermodell aus PEEK mit vier halbkugelförmigen Geometrien am Kieferkamm. Das PEEK-Modell wurde industriell digitalisiert, um einen Referenzdatensatz (REF) zu erhalten. Anschließend wurde das Modell mit folgendem IOS digitalisiert (n=25/Gruppe): Cerec Primescan AC (PRI); Trios 3 Wireless (TRS); True Definition (TRD); iTero-Element (ITE); Cerec AC Omnicam (OMN). Darüber hinaus wurden konventionelle Abformungen mit scanbarem PVS (Flexitime Fast&Scan light flow und Flexitime Monophase Pro Scan) aufgenommen und mit Laborscannern: D810 (D8I) und In EOS X5 (E5I) gescannt (n=25/Gruppe). Die Abformungen wurden gegossen und die resultierenden Gipsmodelle wurden gescannt (n=25/Gruppe) mit: D810 (D8M) und In EOS X5 (E5M). Lineare und Winkelparameter wurden gemessen und mit REF verglichen. Die Einfaktorielle-ANOVA stellte signifikante Unterschiede für alle getesteten Parameter fest. Die höchste Richtigkeit in den Distanzen P17-P13 und P17-P23 wurde von Gruppe E5I und in der Distanz P17-P27 von Gruppe PRI gezeigt. Hinsichtlich der Winkelparameter in der transversalen Ebene zeigte Gruppe D8M die beste Richtigkeit ohne signifikanten Unterschied zu anderen Gruppen, während E5M in der Sagittalebene die höchste Richtigkeit aufwies. Gruppe D8I war in allen linearen Parametern und im Winkel XZ am präzisesten, während Gruppe E5I die höchste Präzision im Winkel YZ aufwies. Die Digitalisierung konventioneller Abformungen lieferte die genauesten Ergebnisse. PRI zeigte ähnliche Werte zur Digitalisierung von Abformungen und war der Digitalisierung von Gipsmodellen überlegen, während TRS und OMN ähnliche Leistungen wie die Digitalisierung von Gipsmodellen zeigten

Trueness of CAD/CAM digitization with a desktop scanner – an in vitro study

Desktop scanners are devices for digitization of conventional impressions or gypsum casts by indirect Computer-Aided Design/Computer-Assisted Manufacturing (CAD/CAM) in dentistry. The purpose of this in vitro study was: 1, to investigate whether virtual models produced by the extraoral scanner have the same trueness as sectioned casts; and 2, to assess if digitization with an extraoral scanner influences the surface information